View Full Version : 2 more vent hood questions. ???????

12-22-2005, 10:18 AM
ok... I have a couple more questions and then hopefully I will fully understand. Thanks in advance for your help.

1. How do I test the hood to make sure its working correctly?

2. How do I know if I am getting "enough" make up air?

12-22-2005, 11:25 AM
Put some incense where your torch sits and if the smoke goes up into your hood then it's working. I don't know the answer about the make up air. In the summer I open my window wide and in the winter I only open it about 1/4 of the way.

12-22-2005, 11:44 AM
I do the incense test as well... except I sit the incense at the back of my chair rather in the area where the torch sits. I do this because I am sitting there not up where the torch is. As for make up air.... I have a 4 inch pipe also located behind the chair so the draft of fresh air comes past me drawing up the bad air out the vent. If you are not feeling and soreness when you are torching you are probably getting enough make up air.... but PLEASE get a detector for your lampwork area. I have mine set up about 8 feet away from the lampwork area.

12-22-2005, 11:55 AM
The incense test is a fair indicator of air flow around the torch and up the hood. To see if it is enough try this. Light the incense with everything set up as you normally work; window or door normally open, hood fan on, etc. Now observe the speed of the smoke flowing up into the hood. Open the door/window a little more; does the smoke flow faster? Then not enough makeup. Continue to open the door/window until you see no change. Now go the other way... slowly and incrementally close the door/window. Does the smoke flow slow down? If it does then you need more makeup so open it back up. Close down the opening until the smoke flow slows then open it up a little and you will have found the optimum door/window opening for those conditions. Remember that air will sneek in through any opening if there is a negative pressure in the room. hat means small openings in the ducting, around the hood sides, under doors, through unsealed outlets, holes in the wall where your propane hose enters; all these can add up to uncontrolled flow from unwanted directions but the incense should show the actual cleansing flow effect at your torch.


12-22-2005, 03:15 PM
Make sure you do the incense test with the torch lit.